Kassel University 2012

Includes bibliographical references.

Front cover ; Title page ; Imprint ; Aknowledgments; Index of Contents; List of Figures; List of Tables; List of Symbols; List of Abbreviations and Acronyms; Abstract; Zusammenfassung; Chapter 1; Introduction; 1.1 Elements of the UMTS Technology; 1.2 Transistors with Wide-Bandgap Semiconductors for UMTS; 1.3 Transistor Modeling for Power Amplifier Design; 1.3.1 Proposed Type of Modeling; 1.3.2 Challenges of Modeling Transistors of Wide-Bandgap Semiconductors; 1.3.3 Challenges of Modeling Advanced Large-Size Transistors for High-Power Amplifiers; 1.4 Main Objectives of the Research Work.

1.5 Outline of the ThesisChapter 2; GaN HEMTs for UMTS Power Amplifiers; 2.1 GaN HEMTs Compared with Devices of Other Semiconductors for UMTS Power Amplifiers; 2.1.1 GaN Compared with GaAs, Si and SiC; 2.1.2 GaN Compared with SiC; 2.1.3 GaN HEMTs Compared with LDMOS FETs of Si; 2.2 Physical Structure and Operation of AlGaN/GaN HEMTs; 2.2.1 Basic Layer Structure and Band Diagram; 2.2.2 Formation of the 2DEG; 2.2.3 Functional Description of Advanced Layer Structures; 2.3 Drawbacks of GaN HEMTs and Modeling Challenges; 2.3.1 Charge-Trapping Induced Dispersion.

2.3.2 Parasitic Effects of GaN Devices2.3.3 Self-Heating Effects on GaN Devices; Chapter 3; Device Characterization for Modeling; 3.1 Manufacturers and Technology of the Studied Devices; 3.2 Data Acquisition for Modeling; 3.2.1 Static-DC IV Measurements; 3.2.2 S-Parameter Measurements; 3.2.3 Pulsed-DC Measurements; 3.3 Large-Signal Characterization for Model Verification3.3.1; 3.3.1 Description; 3.3.2 Measurement Setups; Chapter 4; Proposed Strategy for Small-Signal Modeling; 4.1 Small-Signal Electrical Equivalent Circuit; 4.1.1 Physical Meaning of the Circuit Elements.

4.1.2 Physical Meaning of the Extrinsic CapacitanceParameters4.2 Extrinsic Parameter Extraction; 4.2.1 Analysis of the Generation of Capacitance Ratio Values in the TECR Algorithm; 4.2.2 Proposed Generation of Capacitance Ratio Values; 4.2.3 Equation System of Capacitance Parameters in Pinch-Off; 4.2.4 Sweeps of Values on Capacitance Parameters; 4.2.5 Extraction of Extrinsic Resistance Parameters; 4.3 Intrinsic Parameter Extraction; 4.4 Scalability of the Small-Signal Model; 4.4.1 Scaling Rules in Terms of the Gate Electrode Width; 4.4.2 Scaling Rules in Terms of the Gate Electrode Number.

Chapter 5Results of Small-Signal Modeling; 5.1 Results of Extrinsic Parameter Extraction; 5.1.1 Optimal Frequency Range of the Extraction; 5.1.2 Starting and Optimized Values of the Extrinsic Parameters; 5.2 Results of Intrinsic Parameter Extraction; 5.2.1 Frequency and Bias Dependency of Intrinsic Parameters; 5.2.2 Verification Tests with S-Parameters on Active BiasPoints; 5.3 Small-Signal Model Scalability; 5.3.1 Extracted Parameter Values for Different Device Sizes; 5.3.2 Scalability of Model Parameters in Terms of wfg; 5.3.3 Scalability of Model Parameters in Terms of nfg.

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